1. Field of the Invention
This invention relates to a spring clamp terminal for electrical connection to a conductor by means of a resilient clamp, in particular a spring clamp terminal with an anti-overstress member to prevent overstressing of the spring.
2. Description of the Prior Art
Spring clamp terminals are known from DE 27 06 482, such spring clamps having a base member, and a U-shaped spring arm and actuation member that loops over the base and receives a leading edge of the base through a cutout in the actuation member. Upon depressing the actuation member, the cutout portion below the leading edge enlarges for receiving a conductor therethrough, the actuation member then being released such that the cutout is upwardly biased. A bottom edge of the cutout thus clamps the conductor against a lower surface of the base. One of the problems with this design is that the spring section can be overstressed. Although depression of the actuator is limited by an upper edge of the cutout abutting the base section, actuation of the spring member is typically made by inserting a tool such as a screwdriver tip in a housing cavity above the spring clamp to depress the actuator. The latter can cause overstressing of the spring element even though the actuator is limited in its depression, by pressing on the spring element itself. This problem has been recognized in U.S. Pat. No. 4,171,861 (for example see FIG. 12 of this patent) where a button 52 is moulded and positioned below the spring arm to prevent overbending thereof. The problem with this design is that a separate part is needed, or if the button is moulded directly with the housing, assembly becomes difficult and costly. Furthermore, an anti-overstress feature that is moulded out of plastic is not particularly resistant to damage.